Hi RMC,

What I have mentioned above is basically the answer to a legality matter we have asked ourselves about many moons ago and found appropriate lawyer’s feedback upon.
Hence our trainer’s manual clarifies that during Command upgrades LIFUS both pilots can order a Stop and the actions will always be done according to CM1/CM2 area of responsibility.
The last word on an EMER EVAC (as well as any other emergencies) will always be by the PIC designated, I.e. the trainer.

Within my Operator we do not have and never had 2 Captains flying together unless one of them is a Trainer (LTC and above). However should a Trainer fly on the RHS to fill a missing FO duty (happened on rare occasions), the trainer will comply with all the FO duties contained in the OM-A and will not call for a Stop (except incapacitations).

In my outfit, the trainee CDR in the LHS will perform all RTO actions (since he/she is in the LHS with hands on the thrust levers), but it is always the PIC (LTC/check airman), who makes the stop/go decision. simples...

Sonic bum, Thanks for the additional information. Your trainers manual is ahead of ours and would offer the protection I seek if the worst came to the worst. Ours specifies the trainer only makes the stop go decision and LHS commander PICUS actions the RTO.
unfortunately we do have two Captains flying together most months (normally the senior Captain in LHS) but if it were a trainer in the RHS he cannot command the reject unless LHS becomes incapacitated (as we both described earlier).
Great discussion , clearly, what is most important Is that everyone in a company is clear on who does what.